Oh, boy. It seems there's no end to how much you can mod. So now I see this post and I like the "completely silent" idea

After following the links and looking for alternatives trying to put all the pieces together in my head, why the 2.1mm to 2.5mm adapter? From what I can see, the 2.5mm is on both ends, no need for adapter. What am I missing?
Thanks!

EDIT: sorry, I was looking at another brick that came with 2.5mm The one up here is 2.1. My bad

They fill in where the PSU would have been mounted in the case. The ATX ones can even come with an 80mm fan, say if the PSU fan would have been the only one in the case. There's an option for the single hole or the 3-hole like in your picture above. There's SFX size too.

I am using a couple myself -- one in an Apex MI-008 and another in a Lian-Li PC-Q07. Dig down through all the stuff and there's some pics of them.

They fill in where the PSU would have been mounted in the case. The ATX ones can even come with an 80mm fan, say if the PSU fan would have been the only one in the case. There's an option for the single hole or the 3-hole like in your picture above. There's SFX size too.

I am using a couple myself -- one in an Apex MI-008 and another in a Lian-Li PC-Q07. Dig down through all the stuff and there's some pics of them.